[Seminal vesicle biopsies: Interest in the prostate cancer staging before radiation therapy or brachytherapy]

Objective: Seminal vesicle biopsies (SVB) in the staging of prostate cancer are controversial. Our main objective was to assess their contribution before radiation therapy or brachytherapy. Our secondary objective was to compare pathologic findings of the SVB to the magnetic resonance imaging's (MRI) results.

Patients and methods: From 2000 to 2008, 135 men (median age: 70 years) with prostate cancer (cT1a to cT3) underwent SVB right and left. The median PSA was 12 ng/ml. The median Gleason score was 7. Forty-one patients had an endorectal MRI. The median follow-up was 47 months.

Results: Seminal vesicle involvement was found in 10% of patients. In 9.2% of cases, the biopsy was not contributive. The risk of invasion was significantly associated with the stage T3, the Gleason score up to 7 and the percentage of prostate positive biopsies. A MRI was performed in 41 cases: the correlation between MRI and SVB for the invasion of seminal vesicle was significant but moderate (kappa=0.38). The complications rate of SVB was 10%.

Conclusion: SVB were a simple and profitable method. They have provided supplementary information that could improve the staging and that could lead to the make use of an appropriate treatment. This information was comparable to the information provided by MRI. Further studies should establish their role in relation to MRI and in particular confirm the best specificity of the SVB.